Conventional control systems present operators with a combination of controls such as switches, buttons, levers, knobs, dials, etc. The operators interact with these control systems by manipulating the presented controls in order to execute various control functions. Recently, control systems have become increasingly complex due to the growing number of controllable features. As control systems increase in complexity, control panels become cluttered with switches, buttons, levers, knobs and/or dials. Accordingly, the control systems become more difficult to operate. In addition, it becomes difficult for engineers to design control panels that are capable of accommodating all of the necessary controls within a confined space.
Track pad devices have been developed to address the problems in the related art. These devices are generally two-dimensional (X-Y) and include, for example, capacitive and optical sensing systems. For example, some smart phone devices include optical track pads for navigating the graphical user interface (GUI) of the smart phone. The optical track pads have a pleasant tactile feel, provide an audible “tick” for each move and, unlike capacitive touch screens, can be used without direct skin contact or without the need for special gloves. Some optical track pads work with gloves, such as those that include a mechanical contact that is separate from the track pad for accept or select functions. Furthermore, optical track pads generally have a fairly low resolution infrared camera susceptible to moisture (sweat) interferences and are limited to measurements in two (X-Y) dimensions.